[SQL ] 请问SQL取值的问题

楼主: perasa (金狼钡可汗)   2013-11-12 15:21:52
小弟想要请问一下
SQL这样的写法
为何取不到相关的字段值
============================
SELECT pmm01,pmnud01
FROM pmm_file,pmn_file
WHERE pmm01='G330-130100006' AND pmnud01='test001'
============================
因为在原始表单上pmnud01有给一个字串为test001且pmm01的编号为G330-130100006
不知为何在SQL一直取不到相关的字串或数值
请问这是啥问题造成的呢
谢谢....
作者: bohei (run and fall)   2012-01-12 15:51:00
pmm_file,pmn_file 应串pmm01=pmn01否则会变成cross join...你这句sql大概还在跑吧

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